The employers are among a record 609 businesses that earned the top score of 100, up from 517 or 18 percent over last year. The 2018 index rated a total of 947 organizations.

The index rates companies and top law firms on criteria including workplace protections, same-sex partner benefits, and insurance plans that cover transgender employees through their transition.

“At a time when the rights of LGBTQ people are under attack by the Trump-Pence Administration and state legislatures across the country, hundreds of top American companies are driving progress toward equality in the workplace,” said HRC President Chad Griffin.

Top-scoring companies are establishing policies that affirm and include employees, with some becoming vocal advocates for equality, Griffin said.

Ultimate Software said its “people first” corporate philosophy “means that we respect and value every individual,” said Vivian Maza, chief people officer at Ultimate. She said the index score shows how the company encourages employees “to be themselves at work.”

Weston-based Ultimate Software’s stock has been on the rise as the human resources software company is taking market share from the payroll giants, Wall Street analysts say.

On Tuesday, before earnings were announced, Ultimate’s stock price rose more than 3 percent in Nasdaq trading. On Wednesday,...

The LGBTQ community is not explicitly protected by federal non-discrimination law. But 97 percent of the index-named businesses offer explicit gender identity non-discrimination protections, according to the Human Rights Campaign Foundation.

Fifty-eight percent of the Fortune 500 and over three-fourths of the corporate equality index businesses offer transgender-inclusive health care coverage, up from 0 in 2002, and nearly three times as many businesses as five years ago. In the 2018 index, 103 new employers offer this coverage, the foundation said.

The corporate equality index launched in 2002 to assess LGBTQ-inclusive policies and practices at Fortune 500 companies. The index is a web-based survey. The foundation staff reviews submitted documentation required for language and consistency with the company’s survey answers.

The Human Rights Campaign Foundation is the educational arm of a civil rights organization working to achieve equality for lesbian, gay, bisexual, transgender individuals, and people questioning their orientation. The organization is a nonprofit based in Washington, D.C.